Convergence Analysis of MCMC Algorithms for Bayesian Multivariate Linear Regression with Non‐Gaussian Errors

When Gaussian errors are inappropriate in a multivariate linear regression setting, it is often assumed that the errors are iid from a distribution that is a scale mixture of multivariate normals. Combining this robust regression model with a default prior on the unknown parameters results in a highly intractable posterior density. Fortunately, there is a simple data augmentation (DA) algorithm and a corresponding Haar PX‐DA algorithm that can be used to explore this posterior. This paper provides conditions (on the mixing density) for geometric ergodicity of the Markov chains underlying these Markov chain Monte Carlo algorithms. Letting d denote the dimension of the response, the main result shows that the DA and Haar PX‐DA Markov chains are geometrically ergodic whenever the mixing density is generalized inverse Gaussian, log‐normal, inverted Gamma (with shape parameter larger than d /2) or Fréchet (with shape parameter larger than d /2). The results also apply to certain subsets of the Gamma, F and Weibull families.     

环境监管体制的审视:从重金属污染的角度

严峻的环境形势下,重金属污染仿佛压垮环境监管的"最后一根稻草".基于对A县的微观分析,可以发现职责虚化与协调障碍是环境健康监管体制的首要问题,单一薄弱的监管手段是环境健康监管体制的重要问题.为此,提出"整合性监管"的研究范式,强调:环境监管工具的协同与整合,环境监管各阶段的协同与整合,各环境监管机构的协同与整合,监管式执法与公众参与执法的协同与整合,宏观治理措施与微观治理措施的协同与整合.     

Comparative Study of Predictive Computational Models for Nanoparticle‐Induced Cytotoxicity

With the increasing use of nanomaterials incorporated into consumer products, there is a need for developing approaches to establish “quantitative structure‐activity relationships” (QSARs). These relationships could be used to predict various biological responses after exposure to nanomaterials for the purposes of risk analysis. This risk analysis is applicable to manufacturers of nanomaterials in an effort to determine potential hazards. Because metal oxide materials are some of the most widely applicable and studied nanoparticle types for incorporation into cosmetics, food packaging, and paints and coatings, we focused on comparing different approaches for establishing QSARs for this class of materials. Metal oxide nanoparticles are believed, by some, to cause alterations in cellular function due to their size and/or surface area. Others have said that these nanomaterials, because of the oxidized state of the metal, do not induce stress in biological tests systems. This controversy highlights the need to systematically develop structure‐activity relationships (i.e., the relationship between physicochemical features to the cellular responses) and tools for predicting potential biological effects after a metal oxide nanomaterial exposure. Here, we attempt to identify a set of properties of two specific metal oxide nanomaterials—TiO₂ and ZnO—that could be used to characterize and predict the induced cellular membrane damage of immortalized human lung epithelial cells. We adopt a mathematical modeling approach that uses the engineered nanomaterial size characterized as a dry nanopowder and the nanomaterial behavior in ultrapure water, phosphate buffer, and cell culture media to predict nanomaterial‐induced cellular membrane damage (via lactate dehydrogenase release). Results of these studies provide insights on how engineered nanomaterial features influence cellular responses and thereby outline possible approaches for developing and applying predictive computational models for biological responses caused by exposure to nanomaterials.     

注空气催化氧化渤海稠油降粘工艺可行性探讨

针对SZ361稠油进行了室内空气氧化探索实验，检测和分析了氧化稠油酸值以及尾气中含氧量变化，证实了稠油注空气催化氧化机理，并从理论和技术上论述了该技术的可行性；研究表明：稠油催化氧化有一定效果，氧化5d后，尾气中O2含量（体积分数）从空气中的21%消耗低至仅2.5%；在稠油50g，催化剂用量1.4%，空气压力0.7MPa，反应温度90℃，氧化48h，加水60%，300r/min搅拌的实验条件下，对海上稠油进行催化氧化降粘实验，粘度由2004mPa?s降至100mPa?s，降粘率可达95.0%。     

克拉玛依九9 区齐古组稠油提高开发效果研究

克拉玛依油田九9 区齐古组油藏由于埋藏浅，地层胶结疏松，汽窜出砂严重，影响了油井的生产效果。针对该油藏逐步进入蒸汽吞吐的中后期，采出程度高，油井高含水，产能低，边底水侵入，开采难度加大，产量递减加快，开发效益下降等现状，为了改善油藏整体开发效果，选择该油藏有代表性的井组，利用数值模拟方法对其进行下步开发方案设计与指标预测。数值模拟结果符合油田开发实际。研究表明：克拉玛依油田九9 区齐古组油藏吞吐生产后转连续蒸汽驱对改善生产效果，提高采收率具有一定的积极的作用。     

防治土壤重金属污染面临的主要问题及法律规制

近几年新闻媒体曝光了“毒大米”、“血铅超标”等一批土壤重金属污染致害事件。我国在土壤重金属污染防治工作中,长期以来没有重视土壤重金属污染的特性以及针对这些特性制定相应的法律规范,因此,现如今面临两大困扰：一是历史遗留问题全面爆发;二是缺乏相应法律规制。可以通过借鉴美国“超级基金”制度来建设我国自己的“超级基金”以解决受污染土地的治理问题,同时转变立法导向,重新制定符合重金属污染特征的环境保护标准以实现对土壤重金属污染的规制。     

基于ANSYS的板料成型系统模内加热模块热分析

针对目前板料热成形过程中存在的能量浪费、板料氧化严重等缺点,文章对模内加热方案进行研究探讨,使用ANSYS-Icepack对板料冲压成形的模内加热温度场进行模拟分析,并以此基础做出实物并调试对比模拟状况。结果显示：对于该模架,上下模1 000 W的热源同时加热时,加热组块最高温度可达近400℃,中间板材可加热到300 qC以上,10min之后散热和加热接近平衡。按该模型设计的实际加热系统的温度分布与模拟基本接近。该研究对模内加热模块的设计进行了模拟与初步的试验,将有助于板料热成形技术方面发展。     

湖南省上市公司环境信息披露现状分析及对策

运用内容分析法和比较分析法,对湖南省61家上市公司2011年环境信息披露的模式、内容以及环境信息披露的数量和质量进行量化分析,结果表明：湖南省上市公司倾向于在董事会报告、报表附注以及社会责任报告中披露环境信息;环境信息披露整体水平不高,其中,重污染行业上市公司环境信息披露水平高于非重污染行业。应从落实政府监督责任、明确企业主体责任以及促进公众参与等三个层面入手,努力提高上市公司环境信息披露水平和信息透明度。     

论盗伐林木罪与盗窃罪的关系——与张明楷教授商榷

严重的盗伐林木案件适用“重法条优于轻法条的原则”以盗窃罪论处的观点值得商榷。从客体属性看,盗伐林木罪与盗窃罪之间具有明确的界限;从刑罚量的需求看,盗伐林木罪与盗窃罪之间具有明显的差异。盗伐林木罪与盗窃罪之间不必要也不应当适用“重法条优于轻法条的原则”。一些所谓的“不合理局面”其实具有内在的合理性。     

我国重污染行业环境会计信息披露现状分析

随着人们环境保护意识的加强,企业的经济活动引起了全社会的广泛关注,关于会计行为如何反映企业经营行为对环境影响的研究就成为一项迫在眉睫的课题。对我国重污染行业的环境信息披露情况进行描述性统计分析,发现我国重污染行业企业的环境会计信息总体披露情况普遍不佳并缺乏主动性,有关环境信息披露的法律、法规既不健全也不规范。政府应加强法律法规建设,并建立完整的环境会计核算体系。